The present invention relates to filters and particularly to filters which are cleaned by backwashing.
The cleaning of conventional filters, such as those commonly included in water irrigation systems, usually involves shutting-off the supply line, dismantling the filter, cleaning its parts, and then re-assembling it. Such a procedure is very inconvenient, time-consuming, and costly. A number of backwashing filters have been developed for cleaning the filter without dismantling it.
One such filter as described in my prior U.S. Pat. No. 4,045,345, comprises a housing including an inlet connectable to an upstream fluid pipe, and an outlet connectable to a downstream fluid pipe; a filter body disposed within the housing and having an upstream surface on the housing inlet side thereof to intercept dirt particles in the fluid flowing in the forward direction through the filter body from the housing inlet to the housing outlet; and a backwash nozzle having an inlet opening disposed adjacent to said upstream surface of the filter body for backwashing the filter body. In the construction described in that patent, the backwash nozzle is rotated by the backwashed fluid with respect to the filter body, which body is fixed to the housing.